could israel send in ground troops? >> reporter: well, from the very beginning they talked about enlarging this operation. from the aerial offensive it's been so far, to include a ground invasion of gaza. yesterday, we saw large numbers of troops and tanks moving towards gaza. this morning, we heard that 16,000 reservists have been called up. this is the political season in israel. there's an election in january. it's unclear what the appetite is for a ground incursion. but what is clear, neither israel or hamas nor the other militant groups here are backing down. >> alex marquardt, live in gaza. thanks for your insight this morning. stay safe, alex. >>> moving on to our other big story of the week. david petraeus is expected to face some pretty tough questions this morning over how the cia handled the attack in ben gas save. >> it's the first time top lawmakers had a chance to question petraeus since he was caught up in that sex scandal. abc's preeti arla has a preview from washington. >> reporter: david petraeus heads